Diamond is attracting attention as a material for a semiconductor device because it has excellent semiconductor characteristics in addition to its mechanical, chemical and thermal characteristics. In particular, since diamond has a band gap of about 5.5 eV at room temperature, it is expected to be used as a material for an ultraviolet emission device and an electron emission device using negative electron affinity. Also, since diamond has high breakdown voltage, it is expected to be used as a material for a power device. In addition, since diamond has solid crystallinity, it is expected to be used as a material for an environment-resistant device that is used particularly in severe environments such as high temperature or radiation.
Recently, a diamond power device is actively developed, and a report is made on a Schottky barrier diode having a Schottky junction, a device having a PIN structure, and a device having a combination of a Schottky junction and a PN junction, and the like.
Also, it is known that the dopant incorporation efficiency in the formation of a diamond semiconductor layer depends strongly on the plane orientation of an underlayer.